1. Field of the Invention
The present invention relates to a balloon controller for an endoscopic apparatus and, more particularly, to a balloon controller for controlling a balloon used in an endoscopic apparatus for observing a deep-part digestive tract such as the small intestine or the large intestine.
2. Description of the Related Art
When an insertion portion of an endoscope is inserted into a deep-part digestive tract such as the small intestine, a force for insertion cannot be easily transmitted to the foremost end of the insertion portion due to the existence of complicated bends in the intestinal tract and it is difficult to insert the insertion portion to a deep part, if the insertion portion is simply forced into the tract. For example, if an unnecessary bend or warp is caused in the insertion portion, the insertion portion cannot be inserted to a deeper portion of the tract. A method has therefore been proposed in which the insertion portion of an endoscope is inserted into a body cavity together with an insertion assist implement which caps the insertion portion, and an unnecessary bend or warp in the insertion portion is prevented by guiding the insertion portion with the insertion assist implement.
Japanese Patent Application Laid-Open No. 2002-301019 discloses an endoscopic apparatus in which a first balloon is provided on an insertion portion of an endoscope close to the foremost end of the insertion portion and a second balloon is provided on an insertion assist implement (also referred to as an over tube or sliding tube) close to the foremost end of the insertion assist implement. The first and second balloons can fix the insertion portion and the insertion assist implement in the intestinal tract such as the small intestine by expanding the first and second balloons. This endoscopic apparatus is capable of inserting the insertion portion to a deep portion of an intestinal tract such as the small intestine having complicated bends by alternately inserting the insertion portion and the insertion assist implement while repeating expanding and shrinking the first and second balloons.
In this balloon-type endoscopic apparatus, the pressure in each balloon is measured with a pressure sensor and the balloon is expanded according to the measured pressure value. Therefore, the pressure in the expanded balloon can be controlled at a predetermined set pressure to reliably retain an intestinal tract.